The 350 million chronic carriers of Hepati tis B Virus (HBV) worldwide are at risk of hepatitis, cirrhosis, and hepatocellular carcinoma. A recombinant subunit vaccine is available, but it has a 5-10% failure rate, and there is no widely effective therapy for HBV infection. The development of effective therapies could be advanced more rapidly by a better understanding of the mechanisms of pathogenesis, the immune response, and function of the proteins involved in HBV replication. This conference will gather about 200 scientists who study different aspects of HBV, animal hepadnaviruses, and Hepatitis Delta Virus for discussions of the latest conceptual and technical advances. This meeting has been held annually since 1985, and is the only basic science HBV and HDV meeting of its kind. The primary goal of this application is to raise funds to support travel grants for junior scientists. The 2003 HBV Meeting will be organized by Drs. Antonio Bertoletti and John Tavis. The meeting will be modeled on the successful traditions of this series: intimate interactions through small size, presentation of work-in-progress, and a focus on training younger scientists. The meeting will have 9 oral sessions, two poster sessions, a keynote speaker, and one workshop. The oral session will be: New Models & Viral Entry, RNA & DNA Synthesis, Assembly, Morphogenesis & Trafficking, Regulatory Proteins and Variants, Immune Responses, Pathogenesis, Hepatitis Delta Virus, Hepatocellular Carcinoma & Oncogenesis, and Antivirals & Immunomodulation. Involvement of women and minorities in leadership positions will be emphasized. Each session will have approximately 7 talks selected through peer-review by the organizers of submitted abstracts. Posters for each topic will be presented in the poster sessions. A theme of the meeting will be to compare and contrast HBV with Hepatitis C Virus (HCV), the other most medically important hepatitis virus. The keynote speaker, Dr. Raft Bartenschlager, will contrast the molecular biology of HCB with that of HBV. The workshop will compare HBV and HCV immunology and pathogenesis. This conference will advance HBV research by introducing ideas from the HCV field, promoting constructive interactions between researchers, encouraging exchange of unpublished data and key reagents, and educating graduate students and post-doctoral trainees.